It has long been known that seedlings, and for that matter any growing plant, should be subjected to as little shock as possible throughout its growing cycle.
One of the chief causes of shock is the removal of a small plant or seedling prior to being transplanted in a larger growing receptacle for additional growth prior to final transplanting or when transplanting to the ultimate growth area, as in a field. Thus, if the grower subjects his plants to one or more severe shocks the plant will reward him with less growth and produce. For the purposes of the disclosure contained herein, the term seedling is intended to mean any small plant which is propagated prior to transplanting in the ultimate location wherein it is to mature. Efforts have been made to minimize the shock to growing seedlings when transplanting by providing collapsible or other containers wherein the root system may be removed with a minimum of shock to the plant. For example, U.S. Pat. No. 2,870,575 illustrates a U-shaped individualized compartment, but such are difficult to manipulate and provide only limited drainage. U.S. Pat. No. 3,788,002 illustrates a collapsible container, but drainage openings are centrally located in the bottoms of compartments therein and the root systems tend to grow through and around such openings increasing the shock to the root system as the plant is pulled away therefrom, tending to shatter the plant and its root structure. U.S. Pat. No. 3,667,159 illustrates a seedling flat molded integrally of plastic and having compartments tapering downwardly toward an open bottom. Such receptacles are especially useful in connection with plants having deep root systems, such as pine tree seedlings. The theory is that the plant and its root system may be readily lifted from the downwardly and inwardly tapering compartments, but here again, there is a problem induced by the root system growing through and around the open bottom. Such receptacles are of limited value for growing those seedlings which do not have deep root systems since only minimal amounts of growing medium are available where needed.
The use of other systems, such as peat pots and the like are relatively expensive and the compressed material of the peat pot tends to inhibit the propagation of roots upon transplanting. An excellent method of growing more mature plants for transplanting is exemplified by the disclosure of U.S. Pat. No. 2,829,468 wherein soil blocks or units are compressed into separate squares and a central cavity formed therein for the reception of a small seedling which has been grown in a seedling tray which is not compartmentalized. Substantial shock is induced by removing the seedling for manual transplanting of the root system in the cavity in the blocks of growing medium. As will be observed below, growing trays of the present invention are especially useful in avoiding such shock.
Accordingly, it is an important object of this invention to provide a growing container for seedlings and the like having a side opening drainage channel which permits removal of the root system through an open side of the compartment adjacent the open drainage channel thus minimizing shock to the plant.
Another important object of this invention is to provide a seedling growing device especially adapted to seedling removal from an open side of the compartments with minimal damage to the root system, permitting transplanting in larger squares of growing material for propagation of a more mature plant to be placed in the permanent growing area.
Another important object of the invention is to provide compartmentalized insert strips, a number of which may be carried in a tray for easy removal thereof and for ready reception by a grading means for subsequent transplanting of the graded plants by automatic transplanter means.
Still another important object of the invention is the provision of a growing tray especially for plants such as pine seedlings having deep root systems which can be readily removed from the open side of compartments having side opening drainage channels in the bottom.